Britain is engaged in a "generational struggle" to defeat the Taliban-led insurgency in Afghanistan, Des Browne, the defence secretary, warned yesterday.

Speaking to the Guardian before a meeting of Nato defence ministers in London today, he called for an "honest discussion" about the problems facing the alliance, notably its inability to deploy adequate forces and failure to invest in needed equipment, and the need to "transform" Nato. It was the most successful military alliance the world had ever seen, he said. But it was set up to fight the cold war-type conflicts rather than the expeditionary type operations currently being fought in Afghanistan, and that was something the 26 defence ministers needed to address.

Just 10% of the infrastructure of Nato headquarters in Brussels was devoted to actual military operations, Browne said. And most European countries possessed "static non-deployable forces".

British commanders in Afghanistan have for years asked for more helicopters to move soldiers around relatively safely, and aircraft to supply them with equipment more quickly. Browne said there were many hundreds of helicopters in Europe, but they were not deployable. They didn't have adequate protection and their crews were not trained to special forces levels. He was discussing with other European countries, in particular France, ways to share helicopter resources.

Officials and military commanders in Afghanistan say the Taliban and other insurgent groups are in control of more and more territory and that at best the battle against them has reached stalemate. Browne said: "In Helmand province the Afghan government has a significant presence and a degree of control in every single part of where the people live in any concentration. What people who talk about stalemate mean is that we control that area now ... we have to concentrate on holding and maintaining what we have achieved. We will never be able to expand beyond that unless we can, as it were, backfill with a combination of the Afghan army and their own governance and economic development."

It was a challenge he made no bones about, he said. To reach a state when the Afghans had "ownership of their own security" was going to take time. How long? "It will be a generational struggle," he said. Two generations of Afghans had been denied access to education and law.

Browne suggested that Nato should cooperate more effectively in future with organisations including the EU, which he described as having "complementary capabilities", the UN, the World Bank and the International Monetary Fund.

He will raise concern growing among British military commanders and in Whitehall about US military tactics in Afghanistan with Robert Gates, the US defence secretary, who is attending the London meeting called by Browne. An increasing number of Afghan civilians are being killed in US bombing raids.

According to defence sources, more British special forces are being deployed to Afghanistan in operations against Taliban in the south. Asked about US cross-border operations in Pakistan, Browne said: "We have no intention of going into Pakistan." The insurgency in Afghanistan was a "shared problem" with Pakistan.

There was no prospect of Nato military intervention in Georgia, he said.